This invention relates generally to an improved voltage multiplier and driver circuit for use in a timepiece. It is particularly directed to the provision of a circuit means for energizing a lamp device in a timepiece.
Timepieces for some time now have used backlights to enable viewing where the ambient light condition is relatively poor.
The use of a backlight, particularly in a low voltage battery powered timepiece such as a portable clock or wristwatch, imposes a number of conditions upon the design of the driver circuit, VlZ:
It must have a very low power consumption; PA1 It must be capable of energizing a lamp to luminese, i.e., have voltage-current rating, while operating from a relatively low voltage supply; PA1 It must be inexpensive; PA1 It must utilize a minimum number of components and optimize use of the available space within the timepiece.
The present invention provides an improved voltage multiplier and driver circuit which satisfies the above noted conditions.
The following patents represent some of the prior art pertinent to the field of voltage multipliers and backlights for timepieces: U.S. Pat. Nos. 2,980,816 issued Apr. 18, 1961 to Elmer Curry Payne; 3,673,572 issued June 27, 1972 to Philip O. Sliva; 4,068,295 issued Jan. 10, 1978 to Hubert Portmann; 3,955,353 issued May 11, 1976 to Brian Astle; 3,824,447 issued July 16, 1974 to Tsuneo Kuwabara and 3,008,429 issued Feb. 15, 1977 to James M. Phalan.
These patents are mentioned as being representative of the prior art and other pertinent patents may exist.